using System;
using System.Collections.Generic;
using System.Text;
using System.Net.Sockets;
using System.Threading;
using System.Net;
using SimpleCommunication;
using System.Windows.Forms;

namespace SimpleCommunication
{
    public class Server : IDisposable
    {
        #region DataMember
        public TcpListener listener;
        public Client currentClient;

        private object listenerLock = new object();//锁TcpListener；在BeginAcceptClient，EndAcceptClient，ServerClose这3函数使用；ServerClose之后不能再调用BeginAcceptClient，EndAcceptClient
        /// <summary>
        /// 服务器是否启用监听
        /// </summary>
        public bool serverStart = false;
       
        private EventWaitHandle eventWaitHdl = new EventWaitHandle(false, EventResetMode.ManualReset);

        //在事务处理结束后才触发下列事件
        public event DlgNoParam ServerStartEvent;
        public event DlgNoParam ServerCloseEvent;
        public event DlgOneParam<string> NewClientEvent;
        public event DlgOneParam<string> RecvMsgEvent;
        public event DlgNoParam LocalDisconnectEvent;
        public event DlgOneParam<string> RemoteDisconnectEvent;

        public bool IsConnected => (listener != null && serverStart) ? true : false;
        #endregion

        #region 服务器监听启动关闭和连接接收
        public bool Start(ComboBox Server_IP, TextBox txtPort, int maxClient = 10)
        {
            bool result = false;
            try
            {
                if (!string.IsNullOrEmpty(Server_IP.Text) && !string.IsNullOrEmpty(txtPort.Text))
                {
                    if (Convert.ToInt32(txtPort.Text) > 1024)
                    {
                        IPAddress ipAddr = IPAddress.Parse(Server_IP.Text);
                        IPEndPoint point = new IPEndPoint(ipAddr, Convert.ToInt32(txtPort.Text));
                        listener = new TcpListener(point);
                        listener.Start();
                        result = true;
                        serverStart = true;
                        if (ServerStartEvent != null)
                        {
                            ServerStartEvent();
                        }
                    }
                }
            }
            catch(Exception ex)
            {
                throw ex;
            }
            return result;
        }

        /// <summary>
        /// 有互斥资源
        /// 接收连接主入口，监听启动后调用和每次接收到连接后调用
        /// </summary>
        public void BeginAcceptClient()
        {
            try
            {
                while (true)
                {
                    eventWaitHdl.Reset();
                    lock (listenerLock)
                    {
                        if (serverStart)
                        {
                            listener.BeginAcceptTcpClient(EndAcceptClient, null);
                        }
                        else
                        {
                            return;
                        }
                    }
                    eventWaitHdl.WaitOne();
                }
            }
            catch
            {
                
            }
        }

        /// <summary>
        /// 有互斥资源
        /// 接收到客户端连接时调用到，关闭listener时也调用到
        /// </summary>
        /// <param name="ar"></param>
        private void EndAcceptClient(IAsyncResult ar)
        {
            try
            {
                TcpClient tcpclient = null;
                lock (listenerLock)
                {
                    if (serverStart)
                    {
                        tcpclient = listener.EndAcceptTcpClient(ar);//在这句话之前或者client.BeginRead之前断掉远程客户端都没事，tcpclient都不为null
                    }
                }
                eventWaitHdl.Set();
                if (tcpclient != null)//listener.stop后tcpclient == null,不会进入下面代码
                {
                    InitClient(tcpclient);
                }
            }
            catch
            {
               
            }
        }

        /// <summary>
        /// 有互斥资源
        /// 在listener监听状态下关闭listener时调用，资源释放时调用
        /// </summary>
        /// <returns></returns>
        public bool ServerClose()
        {
            bool result = false;
            try
            {
                lock (listenerLock)
                {
                    if (serverStart)
                    {
                        serverStart = false;
                        listener.Stop();
                        result = true;
                        if (ServerCloseEvent != null)
                        {
                            ServerCloseEvent();
                        }
                    }
                }
            }
            catch
            {
                
            }
            return result;
        }
        #endregion

        #region Client相关操作
        private void InitClient(TcpClient tcpclient)
        {
            currentClient = new Client(tcpclient);
            ClientDlgSubscribe(true);
            currentClient.BeginRead();//即使在这之前服务器断开，该函数返回值也等于1
        }

        /// <summary>
        /// InitClient，CurrentClient_LocalDisconnectEvent，Client_DisconnectEvent调用到
        /// 在事务处理结束后调用到
        /// </summary>
        /// <param name="add"></param>
        public void ClientDlgSubscribe(bool add)
        {
            if (add)
            {
                currentClient.NewClientEvent += new DlgOneParam<string>(Client_NewClientEvent);
                currentClient.RecvMsgEvent += new DlgOneParam<string>(Client_RecvMsgEvent);
                currentClient.RemoteDisconnectEvent += new DlgOneParam<string>(Client_DisconnectEvent);
                currentClient.LocalDisconnectEvent += new DlgNoParam(CurrentClient_LocalDisconnectEvent);
            }
            else
            {
                currentClient.NewClientEvent -= new DlgOneParam<string>(Client_NewClientEvent);
                currentClient.RecvMsgEvent -= new DlgOneParam<string>(Client_RecvMsgEvent);
                currentClient.RemoteDisconnectEvent -= new DlgOneParam<string>(Client_DisconnectEvent);
                currentClient.LocalDisconnectEvent -= new DlgNoParam(CurrentClient_LocalDisconnectEvent);
            }
        }

        public bool SendMsg(string msg)
        {
            bool result = false;
            try
            {
                if (currentClient.SendMsg(msg))
                {
                    result = true;
                }
            }
            catch
            {
                
            }
            return result;
        }

        /// <summary>
        /// 客户端连接情况下断开连接时调用，释放资源时调用
        /// </summary>
        /// <returns></returns>
        public bool DisconnectClient()
        {
            bool result = false;
            try
            {
                if (currentClient != null)
                {
                    currentClient.Dispose();
                    result = true;
                }
            }
            catch
            {
                
            }
            return result;
        }

        public void Client_NewClientEvent(string param)
        {
            if (NewClientEvent != null)
            {
                NewClientEvent(param);
            }
        }

        public void Client_RecvMsgEvent(string param)
        {
            if (RecvMsgEvent != null)
            {
                RecvMsgEvent(param);
            }
        }

        public void Client_DisconnectEvent(string param)
        {
            ClientDlgSubscribe(false);
            if (RemoteDisconnectEvent != null)
            {
                RemoteDisconnectEvent(param);
            }
        }

        public void CurrentClient_LocalDisconnectEvent()
        {
            ClientDlgSubscribe(false);
            if (LocalDisconnectEvent != null)
            {
                LocalDisconnectEvent();
            }
        }
        #endregion

        #region 资源释放
        public void Dispose()
        {
            ServerClose();
            DisconnectClient();
        }
        #endregion
    }
}